Which of the many conferences should you attend? I get this question a lot, so I compiled a list. The list isn't life, it's not a top 10, and it won't say if a conference is naughty or nice, but they are conferences I know about, have attended, or referenced in an article. By no means is this list exhaustive. If you know of a conference people should consider attending, please add them in the comments. If you have an opinion about a particular conference, please comment on that too.

Some have a low opinion of conferences. I'm not one of them. Sure, some conferences can be a waste of time, and those should fade away. And sure, we see a lot more conference-as-monetization strategy these days. But it's conferences that help motivate people to do their best work. Would we see even half the slide decks, papers, or talks describing how people do what they do without conferences as motivation? No we would not. Taking all that wisdom and stuffing it into a presentations is surprisingly hard work. Not something most will do willingly. Humans are event driven. It's these events that help us all build better stuff. And that's a good thing.

The big list of scalability conferences (in no particular order):

Meetups. Meetups are the coffee houses of the enlightenment era, instead of coffee, there's pizza and sometimes beer. Bright people get together to freely discuss their passions. Meetups are topic specific, free, run by passionate people, and are a great source of information. Here in Sillycon Valley, for example, Sebastian runs the excellent Cloud Computing Group Meetup. You'll find meetups for Riak, NoSQL, and almost every conceivable topic. And if there isn't one in your area, start it!

HotOS - focussed on leading edge issues in operating systems. Brings together innovative practitioners and researchers in computing systems. Here's where the future is being made. Combines academic research with a practical bent. 3 days. May. Various beautiful places.

Percona Live - focussed on all things MySQL. Percona are MySQL experts and the conferences are technical in nature. 2 days. London (Oct), New York (May), Santa Clara (April), San Francisco (Feb).

Gluecon - focussed on solving the web application integration, the bits and pieces gluing applications together. This brief means it touches a lot of interesting areas and attracts a great mix of people. 2 days. May. Broomfield, Colorado, near Denver, a pleasant area. Intimate.

Surge - focused on scalability and performance. Put on by OmniTI, long time practitioners in this area. Based on case studies in designing and operating Scalable Internet architectures. Sysadmins, operations, developers, managers. 3 days. September. Baltimore, MD.

Google IO - Famous more for the generous schwag than the technical content, though the technical content is rich. Googlers cover a huge range of topics and go into a lot of technical details. 2 days. May. Held at Moscone Center in San Francisco. Huge.

QCon - focussed on enterprise software development, a practitioner-driven conference conference designed for team leads, architects, and project management. Manages high quality, practicality, and great diversity. 2-4 days. London (Mar), San Francisco (Nov), China (Apr, Oct), and Sao Paulo (Sep).

No Fluff Just Stuff - Focused on the real needs of developers, no marketing. Covers Java, NoSQL, Agile, Web, Mobile, and more. 2-3 days. Various locations in Sep, Oct, Nov.

Hot Interconnects - focussed on researchers and developers of state-of-the-art hardware and software architectures and implementations for interconnection networks of all scales, ranging from multi-core on-chip interconnects to those within systems, clusters, and data centers. 3 days. August. Santa Clara, CA.

ScaleOutCamp - an unconference where early adopters of Cloud Computing technologies exchange ideas. Held in may different areas at many different times. 4 days. Copenhagen (May), Aarhus (Oct).

Apple's WWDC - pretty much the only time Apple says anything, so for that reason it's a must if you are an Apple developer. 5 days. June. San Francisco. Huge. Apple: Tear down those sharing walls!

GOTO - Focussed on the latest developments in Java, OO, .Net, Open Source, Agile, Architecture and Design, Web, Cloud, New Languages and Processes.

PyCon - Focussed on bringing together developers, application designers and business people in the international Python communities. Many different conferences in many different areas. 8 days. March. Santa Clara.

LISA - Focussed on system and network administrators and engineers; it is the crossroads of Web operations, DevOps, enterprise computing, educational computing, and research computing. Oveer the years a great source of influential papers. 6 days. Dec. Boston, MA.

High Performance Transaction Systems (HPTS). Every two years, HPTS brings together a lively and opinionated group of participants to discuss and debate the pressing topics that affect today's systems and their design and implementation. Leading edge topics with top people. 4 days. October. Pacific Grove, CA.

Content Deliver Summit - Focussed on a (very) detailed look at CDN platforms and the delivery of video and rich-media content. It brings together telecom carriers, service providers, content owners, and industry vendors. This is where to go to learn about CDNs. One day. May. New York.

BarCamp - Focussed on learning in an open environment with intense discussions, demos and interaction from participants who are the main actors of the event. One day. Many different camps in many different areas. Their website is a wiki, that should say a lot.

StackOverflow DevDays - Brings some of the biggest names in software to teach you about all the latest and greatest technologies out there. No PowerPoint. Domain experts. Speakers chosen purely on skill. 2 days. San Francisco (Oct), Sydney (Oct), London (Nov), Washington, DC (Dec).

Devopsdays - Brings development and operations together. No two events are alike so not much that can be said about the structure. Often feature: ignite talks, openspaces, and demos. Mountain View - Melbourne - Bangalore - Goteborg.

"Berlin Buzzwords 2012 is a conference for developers and users of open source software projects, focussing on the issues of scalable search, data-analysis in the cloud and NoSQL-databases. Berlin Buzzwords presents more than 30 talks and presentations of international speakers specific to the three tags "search", "store" and "scale"."

CMG (Computer Measurement Group) http://cmg.org/conference/CMG is a not-for-profit, worldwide organization of IT specialists in Performance, Capacity and Service Management.The annual conference is a three day conference with five tracks (IT Service Management; Capacity Management; Application Performance Management; Performance Engineering and Testing; and a Training track).There is an optional training camp before the conference and masterclasses after it.

Todd, are you considering conferences outside the US? Because if you are, I'd add The Fifth Elephant, held every July in Bangalore, India and covering big data and analytics. https://fifthelephant.in/2013/

The Fifth Elephant is only two years old at this point -- and newer than your list -- but it's already fairly well known in India (I'm an organizer).